With 152 ships present at the battle,[8] a large number of these ships were destroyed. This included many capital ships such as the UNSC Trafalgar, the flagship of the Epsilon Eridani Fleet and pride of the Navy.[9]

Starting September 5, 2552 all remaining UNSC starships and their fleets were consolidated under a single command grouping under the UNSC Home Fleet.[10] By the end of the war, the plethora of UNSC starships had been reduced to only a few hundred.[11]

There were a few known ways of identifying UNSC ships. There was the Hull classification symbol, which gives each ship a letter classification and a number. There was the ship emblem, which was a unique image that was special to each ship.

Some warships also used the UNSC REG system, which was also a special serial number.[19][20] There was also the UNc system, which had an unknown meaning.[20]

The UNSC Department of Commercial Shipping operated its own identification codes for freighters that were primarily used in COM transmissions.[21]

MACs are massive coil guns that are used to accelerate projectiles ranging in mass from 600 tons to 3,000 tons, at extremely high velocities. These projectiles are composed of Titanium-A, depleted Uranium, and/or Tungsten with a ferrous (iron) core. They also super heat the metal slugs to make it easier for them to penetrate a target. Super MAC platforms accelerate MAC rounds to over "point four-tenths" the speed of light[24] (120,000 kilometers per second) with twenty-three linear accelerator coils, while ship-based MACs have a lower velocity. Super MAC platforms can also reload a round in 5 seconds, where as the smaller capital ships will need several minutes.

The UNSC frigate UNSC Gettysburg is quoted as firing a 600-ton round at 30 kilometers per second. Before Reach fell, UNSC Pillar of Autumn was equipped with a modified MAC that could quickly fire three lighter projectiles in succession instead of just one heavier projectile. It was originally intended to allow Pillar of Autumn a better chance of disabling a Covenant ship, which was a feature required for a mission that was later scrubbed following the Fall of Reach.

UNSC Infinity has miniature MAC guns along its hull, to compliment its built in, larger MAC guns.